A tornado struck the heart of downtown Atlanta on Friday night, injuring several people and damaging numerous buildings, including the roof of the Georgia Dome as thousands watched a college basketball game, the city's mayor and witnesses said.

Nine people were taken to hospitals, one in serious condition, as a result of the heavy storm, police said.

Police evacuated the multi-story Omni Hotel, which shares a building with the CNN Center, after high winds smashed many windows and scattered debris including furniture into the street below.

Winds also broke some windows at the CNN Center, the television news network's global headquarters, and damaged part of its library, CNN said.

The storm hit the most prominent section of downtown Atlanta, which includes major attractions such as CNN, the Georgia Dome, the Georgia World Congress Center, the Georgia Aquarium and the new World of Coca-Cola that are clustered around Centennial Olympic Park, which was built for the 1996 Summer Olympics.

"We are doing everything in our power to respond to what we now know was a tornado that came through," Atlanta Mayor Shirley Franklin told a news conference. She said the state-run Georgia Emergency Management Agency confirmed the tornado.

Officials temporarily halted the game between Mississippi State and the University of Alabama at the Georgia Dome as high winds damaged the roof, sparking alarm and causing a large monitor hanging high above the court to sway ominously.

A later game in the same stadium was postponed.

Thousands of spectators were also attending a National Basketball Association game between the Los Angeles Clippers and Atlanta Hawks at the Philips Arena, adjacent to the CNN Center complex. The game ended at about 10 p.m.. There was little reported damage to the arena.

The heavy rain and lightning storm started north of the city and swept through downtown about 9:45 p.m., downing at least 37 trees and overturning cars, witnesses and Franklin said.

Emergency services were also searching a building in a suburb of metropolitan Atlanta that partially collapsed "in a pancake fashion," Atlanta fire chief Kelvin Cochran said.

Some 19,000 homes lost power from the storm, Georgia Power officials said.

Some witnesses said they heard a sound like a freight train when the storm hit and saw a funnel-shaped cloud.

"I am very certain that it was a tornado from what I have seen," one female hotel resident told a local television station. She described watching a whirling circle of debris higher than her 12th-story hotel room.

Tornadoes occur frequently in parts of the U.S. South but serious damage from them is rare in major U.S. cities.

The downtown district in Jacksonville, Florida, was hit by a tornado on August 12, 2004, according to the National Weather Service. There were no deaths reported.

Two people were killed when a tornado struck downtown Fort Worth, Texas, on March 28, 2000. The deadliest downtown tornado in a U.S. city in recent decades hit Waco, Texas, on May 11, 1953, killing 114.

(Editing by Peter Cooney)